Temperature effect on compressive strength and quality grading of standard grade concrete with partial replacement of natural coarse aggregate by burnt wood pellet aggregate

Abstract

This research work aims to experimentally investigate the effect of temperature on the standard concrete grade of M50 with partial replacement of natural coarse aggregate by burnt wood pellet aggregate. Concrete with and without burnt wood pellet coarse aggregate was exposed to a temperature of 250℃ for 24 h after 28 days of normal curing. Partial replacement of natural coarse aggregate with burnt wood pellet aggregate was considered having varying percentages 15, 30, 45, and 60% by weight without altering the w/c ratio and dose of polycarboxylate ether-based superplasticizer. Thirty standard cylindrical specimens of size 150 mm diameter and 300 mm length for control concrete and concrete with different replacement levels of burnt wood pellet coarse aggregate were cast to study the response of this concrete in normal as well as exposed to a temperature of 250℃ in terms of strength and its quality grading. The results show that the compressive strength of concrete decreases significantly with increasing burnt wood pellet aggregate. The decrement in compressive strength incorporating burnt wood pellet aggregate is found more significant at the considered temperature than in normal conditions. However, energy dissipation after attaining the peak load increases with an increase in percentage replacement of burnt wood pellet aggregate. The concrete with 60% replacement level under ordinary condition, the quality grading of the concrete was good while with lower replacement levels it was excellent. Upon exposure to temperature, quality grading of the concretes with the lower replacement levels goes down to good however, for the concrete with a 60% replacement level it remains unaffected.